//238.除⾃⾝以外数组的乘积
class Solution {
    public int[] productExceptSelf(int[] nums) {
        int n = nums.length;
        int[] f = new int[n];
        int[] g = new int[n];

        //预处理前缀积数组和后缀积数组
        f[0] = g[n-1] = 1;
        for(int i = 1;i < n;i++){
            f[i] = f[i-1] * nums[i-1];
        }

        for(int i = n-2;i >= 0; i--){
            g[i] = g[i+1] * nums[i+1];
        }

        //使用
        int[] ret = new int[n];
        for(int i = 0;i < n;i++){
            ret[i] = f[i] * g[i];
        }

        return ret;
    }
}